A 43-Year-Old Brazilian Man With a Chronic Ulcerated Lesion

Diagnosis: lacaziosis, or lobomycosis [1]. The diagnosis was confirmed by direct examination of the skin biopsy, highlighting the presence of round or oval yeastlike organisms 6–12 μm in diameter, either isolated or in chains, with a birefringent membrane (Figure 1). The periodic acid-Schiff–stained and the Gomori-Grocott methenamine silver–stained sections of the sample revealed short chains of lemon-shaped fungal cells connected by thin, tubelike bridges (Figure 2). Morphology was consistent with the appearance of Lacazia loboi. There was a minor improvement of the lesion after pentamidine treatment, whereas the Leishmania research by microscopic examination, culture, and molecular biology was negative. However, these exams were done after treatment initiation, so an initial coinfection cannot be ruled out. Mycological culturesonSabouraud-gentamicin-cycloheximide withandwithout actidionewereperformedandwerenegativeafter 2 months. The patient is currently under treatment with terbinafine (250 mg twice daily), awaiting surgical excision of the lesion. Lacaziosis, or lobomycosis [1], is a chronic infectious disease that was first described in 1930 in Brazil by the dermatologist Jorge Lobo [2]. Since then, >500 human cases have been reported [3], mainly in Central and South America. The etiological agent, Lacazia loboi ( formerly known as Loboa loboi), an Onygenales dimorphic fungus [4], seems to be saprophytic in vegetation, soil, and water. It gains access to the skin following cutaneous traumatism, or animal bites [5]. After the initial lesion, there is a slow local dissemination period leading to pleomorphic lesions. The typical clinical aspect is generally multiple keloidal lesions, with a smooth, shiny aspect, but can also appear as papules, nodules, ulcers, sclerodermiform, or verrucous plaques [6]. These lesions are painless and hypoor hyperchromic. Clinical diagnosis is generally difficult because of pathology scarcity and frequently atypical cases. For example, infiltrated plaque-type lesions can be mistaken for cutaneous leishmaniasis; lesions with a keloidal aspect can be mistaken for lepromatous leprosy [7]; and lesions with a verrucous, vegetating, or nodular aspect can be mistaken for sporotrichosis, chromoblastomycosis, paracoccidioidomycosis, keloids, or neoplastic processes [6]. The diagnosis is based onmacroscopic examination of the lesions and on direct microscopic examination of biopsy or curettage. The diagnostic feature of Lacazia loboi is the chain of samesized buds, unlike Paracoccidioides, whose buds are smaller than the mother cell. Figure 1. Skin biopsy: round or oval yeast-like organisms from 6 to 12 μm in diameter, isolated or in chains with a bi-refringent membrane; direct microscopic examination (×1000 magnification). Figure 2. Skin biopsy section. Short chains of lemon-shaped fungal cells connected by thin, tubelike bridges (arrow). A, Periodic acidSchiff stain. B, Gomori-Grocott methenamine silver stain (×1000 magnification).